Cassini's Breathtaking New View of Saturn's Enigmatic Hexagon

There are few things in the solar system that has garnered so many oddball theories than Saturn's striking hexagon. From a weird porthole to another dimension (or a gate to hell), to an Illuminati conspiracy (or a message from god), to aliens (of course), this geometric shape, which swirls around the gas giant's north pole, is certainly unprecedented... but it's not supernatural. And in this new Cassini view of the phenomenon, it can be easy to see why so much mystery is attached to it.

The NASA spacecraft is currently in the process of modifying its orbit around Saturn, taking deep, ring grazing dives. In April, the mission will flip its orbit entirely, diving through the planet's ring plane. This is a prelude to Cassini's demise; after over 12 years in orbit, with its fuel low, it will be steered into Saturn's atmosphere. The spacecraft's fiery end is scheduled for September, but before then it's going to zip through the ring plane 20 times to gather as much data from this daring new orbital trajectory.

In short, we can expect a lot more stunning views from the spacecraft before it dies and observations like this one will help planetary scientists better understand the planet's atmosphere, adding more detail to what drives its beautiful hexagon.

Currently, the northern hemisphere is illuminated in sunlight, providing a wonderfully detailed photograph of the mysterious hexagon to be snapped by Cassini's wide-angle camera. Seen in near-infrared light, the central polar vortex appears as a dark circle. This vortex spins rapidly, whereas at lower latitudes, atmospheric winds slow down. This mismatch gives rise to small turbulent storms, called eddies (some of which appear in this image as dark grey circles in the lighter hexagonal banding).

NASA's Voyager missions in the early 1980s first spied the strange feature and in the decades since, scientists have been trying to work out what could be creating this strange atmospheric flow. Though work is ongoing as to how Saturn's hexagon formed and evolved, scientists hypothesize that through the turbulent nature of Saturn's atmosphere in this polar region, the atmospheric gases act like a spinning fluid. In laboratory experiments on spinning beakers with liquids inside, depending on the speed of rotation, turbulent eddies trigger the spontaneous formation of polygons. At just the right speed, a tiny version of Saturn's hexagon can form.